This invention relates generally to medical devices such as coronary stents and, more particularly to a method and system for smoothing medical coronary stents using gas cluster ion beam technology.
A coronary stent is an implantable medical device that is used in combination with balloon angioplasty. Balloon angioplasty is a procedure used to treat coronary atherosclerosis. Balloon angioplasty compresses built-up plaque against the walls of the blocked artery by the inflation of a balloon at the tip of a catheter inserted into the artery during the angioplasty procedure. Unfortunately, the body""s response to this procedure often includes thrombosis or blood clotting and the formation of scar tissue or other trauma-induced tissue reactions at the treatment site. Statistics show that restenosis or renarrowing of the artery by scar tissue after balloon angioplasty occurs in up to 35 percent of the treated patients within only six months after these procedures, leading to severe complications in many patients.
To reduce restenosis, cardiologists are now often placing a small, typically expandable, metal tubular device called a coronary stent at the site of blockage during balloon angioplasty. The goal is to have the stent act as a scaffold to keep the coronary artery open after the removal of the balloon. Stents have been shown to reduce the rate of restenosis to from 16 to 22 percent.
The problem is there are also serious complications associated with the use of coronary stents. Coronary restenotic complications associated with stents occur in from 16 to 22 percent of all cases within six months after insertion of the stent and are now believed to be caused, in part, by surface micro-roughness of the stents themselves. Because of the substantial financial costs associated with treating the complications of restenosis, such as catheterization, restenting, intensive care, etc., a reduction in restenosis rates would save money and reduce patient suffering.
It is therefore an object of this invention to provide an atomic level surface smoothing of medical coronary stents.
It is a further object of this invention to provide surface modification of medical coronary stents by gas cluster ion beams to decrease complication of restenosis.
The objects set forth above as well as further and other objects and advantages of the present invention are achieved by the invention described hereinbelow.
Numerous studies suggest that the current popular designs of coronary stents are functionally equivalent and suffer a 16 to 22 percent rate of restenosis. Although the use of coronary stents is growing, the benefits of their use remain controversial in certain clinical situations or indications due to their potential complications. The application of gas cluster ion beam (GCIB) surface modification such as smoothing or cleaning appears to reduce these complications and lead to genuine cost savings and an improvement in patient quality of life. The present invention is directed to the use of GCIB surface modification to overcome prior problems of thrombosis and restenosis. The atomic level surface smoothing of stents utilizing GCIB in this invention substantially reduces undesirable surface micro-roughness in medical coronary stents.
For a better understanding of the present invention, together with other and further objects thereof, reference is made to the accompanying drawings and detailed description and its scope will be pointed out in the appended claims.